1. Field of Application
The present invention relates to an electronic control apparatus utilized in a motor vehicle equipped with a user validation apparatus, with the electronic control apparatus controlling various operations of the vehicle.
In particular, the invention relates to an electronic control apparatus that enables engine starting and running when a validation result indicates that a user is permitted to drive the vehicle, and that can be activated to perform other functions such as diagnosis of the condition of the engine or other equipment while engine operation is not enabled.
2. Prior Art Technology
In the prior art, motor vehicles have been developed which are equipped with a user validation apparatus having a function of performing a check of user validity and which prevents the vehicle from being driven if a correct result is not obtained from the validity check. Such a user validation apparatus is described in Japanese Patent Laid-open No. 8-218704, for example. An IC (integrated circuit) chip is built into the ignition key of the vehicle and has an ID (identity, i.e., validity) code stored therein, and when the ignition key is inserted into the key cylinder of the vehicle, the ID code is acquired by the user validation apparatus.
The received code is compared with a corresponding code that is stored in the user validation apparatus, to thereby check whether the individual attempting to start the vehicle is a valid user. Various aspects of operation of the vehicle, including engine starting, are controlled by an engine ECU (electronic control unit), and the results of the ID check by the user validation apparatus are supplied to the engine ECU from the user validation apparatus. If the results indicate a valid user then the engine ECU begins control of the fuel injectors, ignition system, etc., of the vehicle engine, to enable engine starting.
In recent years, requirements have arisen for vehicles which are capable of performing failure diagnosis of various equipment relating to engine control, with such failure diagnosis being performed while the engine is halted, i.e., after the ignition key has been actuated to open the ignition switch. For example, it may be arranged that after a predetermined interval has elapsed following switch-off of the engine, the engine ECU is automatically activated by a command produced from an internal timer IC (SOK IC) after a predetermined time interval.
Furthermore, such a vehicle may be equipped with a capability for performing other operations to prepare the vehicle for engine starting, such as initialization processing performed by the engine ECU immediately prior to engine starting. In that case, it may be arranged that the engine ECU can be activated by a command sent from an external source, for example with an activation request being generated by a door lock sensor and transmitted to the engine ECU when a door lock of the vehicle is released. Alternatively, the engine ECU may be provided with an internal timer function whereby after a predetermined time interval has elapsed following deactivation of the ECU and halting of the engine, the ECU is automatically re-activated to perform a function such as diagnosis of vehicle equipment.
However when such a function whereby the engine ECU may be activated while the ignition is switched off is provided in a vehicle that is equipped with a user validation apparatus, then problems are found to arise. Specifically, the user validation apparatus becomes deactivated (e.g., with no electric power supplied thereto) when the ignition switch is open. When the ignition is switched on and communication between the ECU and the user validation apparatus thereby initiated, it is possible that an activation request signal may be received while that communication is in progress. In that case, if the ignition is then switched off before the communication is completed, the ECU will continue to be activated, and a condition will exist whereby the user validation apparatus has been deactivated and a communication failure or validation failure has apparently occurred. In the prior art, occurrence of this condition will result in a communication error being erroneously detected and recorded, although in fact there has been no error caused by apparatus malfunction or insertion of a non-valid ignition key. In practice, this is a serious problem with such a prior art ECU that is used in conjunction with a user validation apparatus.